This disclosure relates to stable electrode structures and, more particularly, a stable, high activity catalyst for use in fuel cells.
Fuel cells are commonly known and used for generating electric power. For example, a fuel cell typically includes an anode electrode which includes an anode catalyst. The anode catalyst is typically supported on a support material such as carbon. A cathode electrode includes a supported cathode catalyst. An electrolyte is arranged between the anode electrode and the cathode electrode for generating an electric current in an electrochemical reaction sustained by a fuel and an oxidant supply through gas diffusion layers (GDL), which typically face the electrode surface on a side opposite the membrane surface. One example electrolyte is a proton exchange membrane (PEM).
One problem associated with fuel cells is the loss of electrochemical surface area (ECA) of the electrode catalysts and the corresponding loss of fuel cell performance. This ECA loss is associated with several key factors: Ostwald Ripening, platinum dissolution/deposition and platinum agglomeration associated with carbon corrosion. In addition, this loss in ECA is exacerbated by the operations effects of fuel cell potential cycling encountered in typical automobile and bus driving cycles.
To date, the most beneficial solutions to this problem have been to control fuel cell potential limits and the reactant environment within the cell during operation as well as start up and shut down (for example, see U.S. Pat. No. 6,835,479 “SYSTEM AND METHOD FOR SHUTTING DOWN A FUEL CELL POWER PLANT”). What is needed is a stable electrode structure and, more particularly, a stable, high activity catalyst for use in fuel cells.